The present invention relates to a Local Interconnect Network (LIN) receiver, and in particular to a LIN receiver having sleep/wake-up functionality.
LIN Receivers are designed to recognize a voltage level on a LIN bus. According to LIN specification 2.1, page 115, voltage dividers having different division ratios are used on the LIN bus and on the power supply, in particular a battery, to evaluate a LIN level on the bus. FIG. 6 illustrates a prior art LIN receiver 600. A voltage divider chain composed of two resistors 602, 604 is connected between a ground voltage GND and a terminal or input LINI to the LIN bus. Another voltage divider chain also composed of two resistors 606, 608 is connected between ground GND and a positive supply voltage of the BVDD bus. The terminal for ground GND may also be connected as negative supply voltage of the bus. Contact points between the two resistors of the two voltage divider chains lead to a positive and negative input, 610, 611 respectively, of an operational amplifier 612 having an output on a line 614, to which received RXD data is provided.
The disadvantage of such an approach is the permanent power consumption of the divider chains and the required semiconductor surface area for implementing high-impedance resistors. This makes a compromise between power consumption and semiconductor surface area necessary. To implement a sleep function, the divider chains may be switched off. This results in that the level on the LIN bus can no longer be correctly evaluated and a wake-up function over the LIN bus is no longer possible. Accordingly, currently available LIN receivers and LIN transceivers having an integrated receiver function have a relatively high power consumption in the sleep mode.
An object of the present invention is to provide a circuit configuration or a LIN receiver having a corresponding circuit configuration that allows the power consumption to be reduced in the sleep mode.